Light guide employing multilayer optical film
CA 2244185 C · Owner: The University Of British Columbia · Inventors: Whitehead, Lorne A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A light guide (42) having a non-light emitting portion (44) made up of multiple layers of first and second substantially non-absorptive longitudinally specular light reflector materials. The index of refraction of each layer differs from the indices of refraction of the immediately adjacent layers, such that the layers collectively have high longitudinally specular reflectivity. The light guide also has a light emitting portion (48) made of prism light guide wall material. A substantially non-absorptive light scattering mechanism (52) is positioned within the non-light emitting portion (44) in opposition to the light emitting portion (48).
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed February 26, 1997 and granted August 20, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 26, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 26, 2019.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.